Furnace with removable coil stand



T. W. MUNFORD FURNACE WITH REMOVABLE COIL STAND Oct. 18, 1949.

2 Sheets-Sheet 1 Filud Dec. 9, 1947 7." W Munfim' 5044 4 his A flforney IN VEN TOR.

Oct. 18, 1949. I 'r. w. MUNFORD 2,485,453

FURNACE WITH REMOVABLE COIL STAND Filed Dec. 9, 1947 2 Sheets-Sheet 2 4 mmvron 7' VV. Munford I e; I "Maw /7/-'$ Arrorney Patented Oct. '18, 1949 FURNACE wrrn REMOVABLE con. STAND Theodore W. Munford, Ottawa Hills, Ohio, assignor to Surface Combustion Corporation, Toledo, Ohio, a corporation of Ohio 7 Application December 9, 1947, Serial No. 790,589

3 Claims. (Cl. 263-40) This invention relates to improvements in furnaces of the cover type which are now widely used for the annealing of coiled strip steel, the coils being arranged in a vertical column on a coil stand and the stack enveloped by a muille for excluding the outside atmosphere and to permit a specially prepared atmosphere to be circulated through and around the stack of coils. A portable heating hood surrounds themuflle for heating the coils.

In furnaces of said type, in order to reduce to a minimum the time a furnace need be kept out of service because of a damaged coil supporting stand, it is desirable that the stand be readily removable from the furnace base for replacement purposes, but this presents the problem of how to provide a gas-tight seal between the steel deck at the. underside of the furnace base and the coil stand where it is surrounded by said deck. There is also the problem of how to support the muflle. The present invention aims to solve these problems in a relatively simple and practical way, and from one point of view the invention may be said to be an improvement over the furnace disclosed in Patent No. 2,414,130.

For a consideration of what I consider to be novel and my invention, attention is directed to the following specification and the claims appended thereto.

In the accompanying drawings forming part of this specification,

Fig. 1 is a vertical section of a furnace embodying the present invention.

Fig. 2 is an enlarged fragmentary sectional view of parts embodied in Fig. 1.

Fig. 3 is a view similar to Fig. 2 but showing a slightly different arrangement of parts.

Fig. 4 shows a modified form of the invention.

Referring to the drawings, the furnace comprises a furnace base In for supporting one or more coil-supporting stands ll (only one stand being shown), a portable heating hood l2 common to all of said stands, and a bell-type muille l4 individual to each stand for enveloping the coils l3 thereon whereby to exclude the outside atmosphere therefrom and to permit a specially prepared atmosphere to'be circulated about the coils during the annealing operation. The heatthe muilie. In the drawings, only the top and bottom tubes are shown but as indicated by the connecting line Hi there will be a series of such tubes therebetween. The heating hood seats on an upright peripheralv wall H on the furnace base, and the seating joint is surrounded by a conventional sand seal l8. The coils l3 are separated from each other by conventional spacers I 9.

- The furnace base In comprises underlying floor beams 22 supported on an elevated structure 23 whereby the underside of the base is openly exposed to atmospheric air and whereby access may be had to a fan motor 24 which is secured to the underside of the coilstand H for driving a circulating fan 25 coaxial with a control opening 3| in the top plate 26 of the coil stand, the fan being interposed between the said top plate and a lower plate 27, the function of the fan being to circulate the atmosphere within the muiile I through and around the pile of coils I3 on the stand. The two plates 26 and 21 are maintained in spaced relation by 'a plurality of radially extending wall plates 30 in circumferentially spaced relation whereby to provide radial gas passages between the fan 25 and the muflie H. The special atmosphere is supplied to the .muflle by a supply pipe not shown but entering through the bottom of the coil stand.

The coil stand has a bottom base plate 32 which seats directly on the fioor beams 22 on the base; hence, the underside of the plate is openingly exposed to atmospheric air. The intermediate plate 21 of the coil stand and the base plate 32 are separated from each other by a c0ncentric series of wall-type spacer rings 33 and by a filling 34 of heat insulating concrete between said ring's, the primary function of the rings being to absorb a shock of impact of dropping a coilon the top plate 26 of the stand; however, this arrangement is optional insofar as the present invention is concerned. Except where the coil stand is positioned, the floor beams 22 of the furnace base are covered with a gastight sheet-metal deck 35, it being understood that it is on thisdeck that the peripheral brick wall II is seated and that the otherwise exposed top-side of the deck is covered with a cast layer of heat-insulating material 36.

ing hood embodies radiant tubes 15 for heating 9 To prevent leakage of gas out of the furnace,

it is necessary to provide a gas-tight connection between the coil stand and the surrounding steel deck 35, and it is also necessary to provide a suitable support for the foot of the muiile N. In the present invention, these requirements are met in a relatively simple and practical manner as will now be explained.

In the present invention, the seal between the coil stand and the surrounding deck comprises a horizontally disposed annular plate 31 coaxial with said stand. This plate (hereinafter sometimes called a bridge plate) is supported in part by said stand in a manner presently explained and in part by an annular pedestal which is welded gas-tight to. the steel deck 35 and which is coaxial with said stand. The muiiie I4 is removably seated on this bridge plate 31 and obiectional leakage of gas out of the muille under its foot is prevented by a layer of sand ll disposed around the lower portion of the muiiie.

To prevent leakage of gas out of the furnace by way of the seat between the pedestal II and the bridge plate I'Lthe latter is provided with a depending endless blade 42 coaxial with the pedestal and the space between the blade and pedestal is filled with a plastic sealing material 43. This material must necessarily be in place before the bridge plate 31 is seated on the pedestal and, therefore,.there is mounted on the steel deck 35 coaxial withsaid blade an upstanding endless wall 44 to form an endless channel or trough wherein the plastic sealing material may be initially placed for penetration by the blade 42 as will now be readily understood.

As indicated at 45 in Fig. 2, the inner rim of the bridge plate 31 is welded gas-tight to an upright supporting wall 46 which surrounds the coil stand, this wall being welded gas-tight at its lower edge, as indicated at 41, to the base plate 32 of the coil stand. It will, therefore, be understood that according to Fig. 2 the bridge plate 31 is integral with thecoil stand and that the means for making a gas-tight connection between said plate and said stand comprises the wall and the welds 45 and 41. However, as

shown in Fig. 4, the gas-tight connection may be otherwise made, the bridge plate in this view being indicated by reference numeral 38.

- In Fig. 4' the base plate 32 of the stand is ex- I tended outwardly somewhat farther than in Fig. 2 whereby to provide between the outer peripheral wall 50 of the stand and an upstanding wall 5| welded gas-tight to the outer portion of said base plate an annular trough or channel around the stand for plastic sealing material of the same character as the sealing material 43. The bridge plate 38 is adapted to overlie and rest on the wall 5|; hence, this wall may be considered as a pedestal on the stand for supporting the bridge plate in conjunction with the other pedestal 40 on the metal deck 35. At its inner edge the plate 3'! is provided with a depending blade 52 coaxial with the coil stand for penetration into the initially plastic sealing material in the underlying trough whereby to form ages-tight seal between said plate and the coil stand as will nowbe readily understood.

In Fig. 2 sand from around the foot of the mufile H is prevented from entering the space between the upper and intermediate plate 26 and 21 of the coil stand by an upward extension 53 of 1 the lower-encircling wall 46; in Fig. 3 the sand barrier is formed by an upstanding wall 54 mounted on the bridge plate 31 itself, and in Fig. 4 the barrier is formed by an upstanding wall 56 to prevent sand from the pile 4| thereabove from working under said plate at the pedestal ll.

It will be readily appreciated that the arrangement of parts in Fig. 3 is to all intents and purposes the same as in Fig. 2 and, therefore, need not be further described.

In the present invention it serves no useful purpose to extend the steel deck ll of the furnace base under the coil stand; hence, said deck is terminated short of said stand, it being observed that there is an air gap between said stand and said deck. One practical advantage of not extending the deck beneath the coil stand is that it aifords no seat for lodgement of foreign matter that might interfere with a proper seating of the coil stand at its station on the furnace base.

As previously stated, the protective gas or atmosphere for the coils I3 is supplied to the muiile It by a supply pipe not shown but extending through the bottom of the coil stand. There is no outlet pipe for said atmosphere; hence. a slight positive pressure tends to prevail in said music. Some leakage of gas out of the muille by way of the sand seal M aroundthei'oot thereof is not objectional butinstead is desirable as it insures the presence of a relatively fresh atmosphere in the muiiie at all times. The sand seal I8 around the foot of the heating hood I! prevents infiltration of air into the hood and permits a plenum of the gas from the muliie to prevail in said hood, and as will now be readily understood the seal between the coil stand and the metal deck of the furnace base serves the same purpose.

What I claim is: 1. A furnace comprising, in combination, a stand for a charge of material to be heat treated, a furnace base having underlying floor beams and a station on said beams where said stand is removably seated, a sheet metaldeck on said floor beams except at said station and surrounding the stand in spaced relation to provide a clearance gap therebetween, a horizontally disposed annular plate encircling said stand and overlying said gap, an annular support mounted on said stand in gas-tight connection therewith for supporting the inner edge portion of said annular plate, and another annular support mounted on the deck in gas tight connection therewith for supan annular support mounted on said stand in gas tight connection therewith for supporting the inner edge portion of said plate, and another annular support mounted on the deck in gas tight connection therewith for supporting the outer edge portion of said plate. the annular support on the stand being laterally spaced from the side wall of the latter to form therewith a trough for sealing material, and said annular plate having a depending blade for extending into said trough for enveloprnent by the sealing material therein.

5 6 3. A furnace comprising, in combination, a REFERENCES CITED Stand for a chargfi of material to be heat treated, h references e o ec d in a furnace base having underlying floor beams and a station on said beams where said stand is reme of this patent movably seated and the stand comprising a base 5 NITE STATES PATENTS plate which rests on said beams, a sheet metal Number Name p g e on sa d floor beams except at said station 2,169,621 Taylor Aug 15, 1939 and surrounding said base plate in spaced rela- 2,249,411 woodson July 15, 1941 tion to provide a clearance gap therebetween. a horizontally disposed annular plate encircling 0 said stand and overlying said gap, and means comprising said annular plate for forming a gas tight seal between said base plate and said deck. THEODORE W. MUNFORD. 

